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1.
The atomic coherent population trapping in the system of an atom with one ground state, a pair of excited states and a set of continuum states, interacting with two temporally separated sets of laser pulses with different phases is investigated. The relative phases of laser pulses on the amount of atomic populations trapped in the three bound states and the efficiency of population transfer are analyzed. 相似文献
2.
We have investigated the photoionization properties of an atom with a ladder coupling scheme involving two autoionizing states coupled to each other.The effects of the coherent coupling between two autoionizing states and between the low-lying autoionizing state and the continuum on the ionization yield are discussed.The conditions leading to atomic coherent population trapping and the coherent population trapping states are given explicitly. 相似文献
3.
We investigate the atomic coherent population trapping in the system of two-mode quantized field interacting with a A-configuration atom with two lower bound states, one autoionizing state and a flat atomic continuum. The states of the field which traps the atom in its two lower bound states are given and the influence of the field induced continuum structure is examined. 相似文献
4.
5.
原子相干对里德伯原子稳定性的影响 总被引:1,自引:1,他引:0
研究了含级联双光子过程的多束缚态激光场诱导原子连续态结构系统中原子的相干捕获,给出了产生相干捕获的条件及暗态的表达式,讨论了原子初态和激光强度对原子相干捕获及粒子布居值在束缚态上分布的影响,揭示了原子相干对稳定里德伯原子的重要作用。 相似文献
6.
ATOMIC COHERENT POPULATION TRAPPING AND ITS APPLICATION IN A RAMAN-TYPE PHOTOIONIZATION SYSTEM WITH THREE BOUND STATES 下载免费PDF全文
We have studied the atomic coherent population trapping in a Raman-type, photoionization system with three bound states. The conditions for the system having two or one stable eigenstate are given. The influences of Fano asymmetric factors on the coberent population transfer are also analyzed.It is found that the property of the system having on]y one population trapping state consisting of the ground state, and one excited state, can be utilized to transfer the atomic initial population into one excited state. 相似文献
7.
Wanare H 《Physical review letters》2006,96(18):183601
We demonstrate the simultaneous occurrence of coherent population trapping at a series of frequencies separated by modulation frequency of phase-modulated fields. The two arms of the system are coupled to two phase-modulated fields and the response of the atomic system to such fields is calculated nonperturbatively. A judicious choice of modulation characteristics allows one to selectively switch on or off the occurrence of coherent population trapping at specific frequencies. A new technique is developed to compute two-dimensional tridiagonal matrix equations. This generalized technique provides the vital methodology needed to calculate the response of such systems in the strong modulation regime and for arbitrary field strengths. 相似文献
8.
研究了少周期脉冲串作用下三能级原子中的布居转移和相干布居捕获现象.在非旋波近似的情况下求解了密度矩阵方程.研究结果表明在等时间间隔的锁相脉冲作用下,系统能级的布居逐步转移并积累,系统基态相干也逐步积累.在满足脉冲重复频率为基态能级频差的整数分之一倍时,三能级系统和频率梳中两梳齿频率成分作用形成相干布居捕获现象,原子暗态布居值达到最大,介质对脉冲透明.在适当选取少周期脉冲参量的情况下,在0.5个ns的时间内三能级系统相干性演化到最大后到达稳态,相干布居捕获发生.与脉宽为100个fs的多周期脉冲相比,少周期脉冲串在介质中建立相干布居捕获的时间缩短两个数量级.由于频率梳中与三能级系统发生作用的梳频成份有相同的频移,相干布居捕获的条件双光子共振仍然满足.因而,当两基态能级频率差较大时,如果选取少周期脉冲载波频率为系统能级1至2和1至3的传输频率之和的一半ω=(ω1+ω2)/2,室温下原子热运动的引起的多普勒频移并不会破坏相干布居捕获. 相似文献
9.
Min Xie 《Optics Communications》2009,282(9):1819-1824
We investigate quantum interferences in coherent population trapping of a cold double Λ-type four-level atomic system driven by two counterpropagating laser fields. We study both decoherence and enhanced-coherence actions resulting from the multi-transition pathways in building up the trapping state, and analyze the system operating with and without external coherences in various configurations of the atomic dipole moments. 相似文献
10.
B. G. Matisov I. A. Grigorenko N. Leinfell’ner I. E. Mazets A. Yu. Snegirev 《Technical Physics》1998,43(6):631-636
Equations are derived which describe the dynamics of three-level atoms with a Λ level scheme, interacting with two coherent
resonance fields under conditions such that cooperative relaxation predominates over incoherent spontaneous emission. A numerical
calculation of the temporal dynamics of the values of the atomic populations is performed. It is shown that coherent population
trapping in the presence of cooperative decay is possible. The quantities characterizing this phenomenon are calculated—the
width of the black line and the transition time to coherent trapping in this scheme.
Zh. Tekh. Fiz. 68, 19–24 (June 1998) 相似文献
11.
Stable 85Rb micro vapour cells: fabrication based on anodic bonding and application in chip-scale atomic clocks 下载免费PDF全文
We describe the microfabrication of 85 Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb.Under controlled conditions,the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm 3 internal volumes during the cell sealing process.At an ambient temperature of 90 C the optical absorption resonance of 85 Rb D1 transition with proper broadening and the corresponding coherent population trapping (CPT) resonance,with a signal contrast of 1.5% and linewidth of about 1.7 kHz,have been detected.The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status.In addition,the physics package of chip-scale atomic clock (CSAC) based on the cell was realized.The measured frequency stability of the physics package can reach to 2.1×10 10 at one second when the cell was heated to 100 C which proved that the cell has the quality to be used in portable and battery-operated devices. 相似文献
12.
Two-dimensional laser cooling based on velocity-selective coherent population trapping is investigated theoretically for the J
g=1J
e=0 atomic transition. Wavevectors and polarizations of three laser beams are chosen to realize a coherent superposition of three degenerate ground states. For the first time in laser cooling, use is made of the electric field phases to realize coherent population trapping selective in two dimensions. Numerical solutions and analytic estimates are presented for laser cooling of helium atoms. 相似文献
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14.
L. V. Il’ichev 《JETP Letters》2011,93(8):442-446
The properties of a one-dimensional atomic Bose condensate are studied under the assumption that the condensation leads to
a state of velocity-selective coherent population trapping. This state is characterized by the quantum correlation (entanglement)
between the intrinsic angular momentum of an atom and its translational motion underlying nontrivial features of the condensate.
The effects of weak interatomic interaction are taken into account. The steady state of above-condensate atoms corresponding
to the slow decay of the state with coherent population trapping is found. The dynamic problem concerning the evolution of
the system of above-condensate atoms after switching off the optical field forming the state with coherent population trapping
is solved. The solution is found by the diagonalization of the Hamiltonian based on introducing the Bogoliubov quasiparticles
with the unusual dispersion law. 相似文献
15.
We have investigated coherent population trapping (CPT) in laser-cooled as well as room-temperature (with and without buffer gas) rubidium atoms. The characteristic broad signal profile emerging from the two-photon Raman resonance for room-temperature atomic vapour is consistent with the theoretical calculation incorporating associated thermal averaging. The spectral width of the dark resonance obtained with cold atoms is found to be broadened, compared to room-temperature vapour cell, due to the feeble role played by thermal averaging, although the cold atomic sample significantly overcomes the limitation of the transit time broadening. An alternative way to improve transit time is to use a buffer gas, with which we demonstrate that the coherent population trapping signal width is reduced to < 540 Hz. 相似文献
16.
YANG Guo-Jian XIA Li-Xin XIE Min 《理论物理通讯》2006,46(9)
Based on the theory of velocity-selective coherent population trapping, we investigate an atom-laser system where a pair of counterpropagating laser fields interact with a three-level atom. The influence of the parametric condition on the properties of the system such as velocity at which the atom is selected to be trapped, time needed for finishing the coherent trapping process, and possible electromagnetically induced transparency of an altrocold atomic medium,etc., is studied. 相似文献
17.
YANG Guo-Jian XIA Li-Xin XIE Min 《理论物理通讯》2006,46(3):556-560
Based on the theory of velocity-selective coherent population trapping, we investigate an atom-laser system where a pair of counterpropagating laser fields interact with a three-level atom. The influence of the parametric condition on the properties of the system such as velocity at which the atom is selected to be trapped, time needed for finishing the coherent trapping process, and possible electromagnetically induced transparency of an altrocold atomic medium, etc., is studied. 相似文献
18.
A novel scheme for optical bistability in a coherently driven three level atomic system is proposed. The scheme utilizes the non absorption resonance which occurs due to a population trapping in a coherent superposition of the ground state sublevels. The resulting optical bistability occurs for a lower threshold power than for a two level system and is insensitive to Doppler and laser bandwidth effects. 相似文献
19.
D. Miletic C. Affolderbach M. Hasegawa R. Boudot C. Gorecki G. Mileti 《Applied physics. B, Lasers and optics》2012,109(1):89-97
We report on studies on the light-shift in caesium miniature atomic clocks based on coherent population trapping (CPT) using a micro-fabricated buffer-gas cell (MEMS cell). The CPT signal is observed on the Cs D1-line by coupling the two hyperfine ground-state Zeeman sublevels involved in the clock transition to a common excited state, using two coherent electromagnetic fields. These light fields are created with a distributed feedback laser and an electro-optical modulator. We study the light-shift phenomena at different cell temperatures and laser wavelengths around 894.6?nm. By adjusting the cell temperature, conditions are identified where a miniature CPT atomic clock can be operated with simultaneously low temperature coefficient and suppressed light-shift. The impact of the light-shift on the clock frequency stability is evaluated. These results are relevant for improving the long-term frequency stability of CPT-based Cs vapour-cell clocks. 相似文献
20.
The physics package of a chip-scale atomic clock (CSAC) has been successfully realized by integrating vertical cavity surface emitting laser (VCSEL), neutral density (ND) filter, λ/4 wave plate, 87Rb vapor cell, photodiode (PD), and magnetic coil into a cuboid metal package with a volume of about 2.8 cm3. In this physics package, the critical component, 87Rb vapor cell, is batch-fabricated based on MEMS technology and in-situ chemical reaction method. Pt heater and thermistors are integrated in the physics package. A PTFE pillar is used to support the optical elements in the physics package, in order to reduce the power dissipation. The optical absorption spectrum of 87Rb D1 line and the microwave frequency correction signal are successfully observed while connecting the package with the servo circuit system. Using the above mentioned packaging solution, a CSAC with short-term frequency stability of about 7 × 10^-10τ-1/2 has been successfully achieved, which demonstrates that this physics package would become one promising solution for the CSAC. 相似文献